Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H7/00—Gearings for conveying rotary motion by endless flexible members
  • F16H7/24—Equipment for mounting belts, ropes, or chains
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F58/00—Domestic laundry dryers
  • D06F58/02—Domestic laundry dryers having dryer drums rotating about a horizontal axis
  • D06F58/04—Details 
  • D06F58/08—Driving arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/32—Friction members
  • F16H55/36—Pulleys
  • F16H55/49—Features essential to V-belts pulleys

Definitions

• This invention relates generally to belt driven machines, and in particular to a combined pulley and belt locator which transmits power to a drive belt and maintains the belt at a proper operating position.
• Many appliances have an endless belt which transmits power and motion from a motor to a driven component.
• an automatic clothes dryer has an electric motor which drives a flexible belt to rotate a drum containing wet clothing.
• a pulley is mounted along an end of a motor drive shaft and rotates with the shaft for moving the belt.
• the pulley typically is threaded onto a corresponding threaded portion of the shaft.
• the belt engages the pulley and is aligned with a belt-driving section of the pulley.
• a blower is also attached to the drive shaft for circulating air through the dryer to remove moisture from the clothing as it tumbles in the drum.
• the motor is frequently located in a dryer housing at a position which is not easily accessible nor in view.
• a person performing initial assembly of the dryer or subsequent maintenance must install the belt "blindly,” without seeing the pulley.
• the belt may inadvertently be misaligned, or be installed around the shaft instead of the pulley. That produces improper belt tensions and uncertain speed ratios which reduce the life of the belt and lead to operational failure.
• a belt restrainer has frequently been installed on the shaft adjacent to the pulley.
• the belt restrainer, or belt guide is typically a plastic shroud having an external surface sloping toward the pulley which, when rotated, causes a misplaced belt engaging the surface to move to its proper position on the pulley.
• the belt guide has an internal collar for mounting on the drive shaft and a series of internal ribs which support the structure of the shroud.
• An example of such a belt guide is described in U.S. Patent No. 4,929,219, issued May 29, 1990 and entitled "Belt Locator For Locating A Belt On A Pulley.” [0004]
• the belt guide can lead to additional expense and delay. Workers occasionally forget to install a belt guide, or install it on the drive shaft in a backwards orientation with the surface sloping away from the pulley.
• the plastic material of the belt guide can be less durable than other surrounding parts which are metallic. Moreover, the production costs associated for molding the plastic guide adds to the substantial costs already required for machining the pulley. [0005] Production of the pulley can also be relatively inefficient. It is made from a solid piece of steel which is machined to define the complex geometry and to eliminate any sharp edges which could damage or destroy the belt. Pulleys have not typically been made by a die casting process because molded parts often exhibit discontinuities in surface contours (referred to as "parting lines") forming sharp edges which rapidly abrade the belt and lead to premature failure.
• the invention is a drive pulley and belt guide for a belt-driven machine.
• the combination comprises a one-piece body having a belt-driving section and a belt- guiding section.
• the belt-driving section includes a hub configured for engagement by a belt.
• First and second end walls are on the hub, and an internal passage extends through the hub.
• the belt-guiding section has an external surface which extends from the second end wall and flares conically outward from the second end wall to an end of the body.
• the belt-guiding section also has an internal surface which extends from the internal passage to the end of the body.
• the internal surface is substantially free of reinforcing members and defines a hollow, cup-shaped interior free of structure within the interior.
• a system transmits power to a belt-driven device.
• the system comprises an electric motor, and a drive shaft connected to the motor for rotation on an axis.
• a pulley is mounted on the drive shaft.
• An endless belt engages the pulley and is supported for transmitting power to the device.
• the pulley has a belt-driving section configured for engagement by the belt and a belt-guiding section integral with the belt-driving section.
• the belt-guiding section has a conically-tapering external surface and an internal surface which is substantially free of reinforcing members and defines a hollow, cup-shaped interior free from structure within the interior.
• the pulley further has an internal tubular passage for receiving the drive shaft to mount the pulley on the shaft with the shaft extending through the passage.
• the shaft further extends through the interior of the belt-guiding section without contacting any structure therein.
• FIG. 1 is a schematic perspective of an automatic clothes dryer with portions partially broken away to show internal construction;
• FIG. 2 is an enlarged portion of Fig. 1 showing an electric motor and belt;
• FIG. 3 is a side elevation of the clothes dryer;
• FIG. 4 is an enlarged side elevation of a one-piece pulley and belt guide combination; [0015] FIG. 5 is a perspective of the pulley of Fig. 4; [0016] FIG. 6 is a section taken along line 6--6 of Fig. 4; and
• FIG. 7 is a section similar to Fig. 6 but for a pulley of a second embodiment.
• Corresponding reference characters indicate corresponding parts throughout the views of the drawings. Detailed Description of the Preferred Embodiments
• the pulley 10 has a one-piece body which transmits power from a drive shaft 14 to a belt 16 and maintains the belt at a proper operating position.
• the pulley 10 is particularly suited for use in applications where the belt 16 may become positioned at an improper location relative to the pulley.
• the pulley is intended for use inside the housing 18 of an automated clothes drying machine, or dryer 20, as shown in Figs. 1-3.
• the belt 16 must be installed blindly (i.e., without direct viewing) and is therefore more likely to be placed at an incorrect location.
• the belt 16 is subject to vibrations and tension variations which can lead to its becoming dislodged from a correct location during operation of the dryer 20.
• the dryer 20 includes a housing with a rotatable drum 22 for receiving wet clothing.
• the belt 16 is trained around an outer periphery of the drum 22 in frictional engagement therewith.
• An idler system 24 is provided for taking up any slack in the belt.
• the idler system includes a wheel rotatably mounted on a resilient arm such that the wheel is biased to tension the belt 16 and maintain an appropriate amount of tension on the belt so that rotation of the pulley 10 accomplishes rotation of the drum 22, as will be understood by those skilled in the art.
• An electric motor 26 is mounted in the dryer housing 18 for driving
• the motor 26 is conventional and, as known to those skilled in the art, includes a stationary assembly, or stator 28 (Fig. 2), and a rotatable assembly, or rotor 30.
• the stator 28 is generally annular and holds one or more wire-wound coils, or windings (not shown). When energized with electrical current, the windings magnetically interact with the rotor to produce torque. The torque is transmitted to the horizontal drive shaft 14.
• the motor 26 is elevated from the bottom of the housing 18 and is mounted on two hub rings 32 positioned at opposite ends of the motor which are supported by two corresponding legs 34. V
• the hub rings 32 have suitable material (e.g., rubber) for absorbing shocks and damping vibrations.
• Each hub ring 32 is placed in a crescent shaped cradle on a corresponding leg 34.
• a thin metallic clip 36 is installed above each hub ring 32 to secure it to the leg 34:
• the drive shaft 14 extends to a rear portion of the housing 18 to drive a blower (not shown) to circulate air through the dryer 20.
• the blower induces ambient air to be drawn through an inlet port (not shown).
• the air is heated and directed into the drum 22 for contacting clothing and removing moisture from fabrics as clothing tumbles in the drum.
• the belt 16 illustrated in the drawings is a multiple groove or "poly- V" belt which, on one face 38 (Fig.
• the belt 16 is formed of a suitable flexible and durable material, such as rubber. It is supported for lengthwise movement in an endless path from the pulley 10, to the idler 24, around the drum 22 and back to the pulley for transmitting power to the drum for rotation.
• the pulley 10 is mounted on an end portion of the drive shaft 14, it may be located at any portion therealong.
• the pulley 10 has a one-piece construction which includes a belt-driving section (generally indicated at 40) for engagement by the belt 16 and a belt-guiding section (generally indicated at 50) for preventing incorrect placement of the belt and/or causing a misplaced belt to move toward the belt-driving section.
• the belt-driving section 40 comprises a generally cylindric hub 52 having a central axis A and an exterior formed with several annular ribs 54 and grooves 56 in an alternating arrangement for receiving corresponding formations on the belt 16.
• First and second end walls 60, 62 extend radially outward from the hub 52 adjacent opposite ends of the hub for containing the belt 16. The first (right in Figs.
• end wall 60 has an outer face 64, a peripheral edge 66, and an inner wall 68 which slopes from the peripheral edge to the hub 52.
• the peripheral edge 66 preferably has an external shape which is suitable for being gripped by a tool or by hand for being installed on the shaft 14.
• the peripheral edge 66 of the first end wall 60 is polygonal, more specifically, hexagonal.
• a groove 70 in the outer face 64 of the first end wall 60 reduces the weight of the body (and cost) by removal of unnecessary material.
• the second (left in Figs. 4-6) end wall 62 has a conical inner face 72 and an outer face 74 (Fig. 6).
• An internal passage 80 extends axially through the hub 52 for receiving a portion of the shaft 14 to mount the pulley 10 on the shaft.
• the internal passage 80 has screw threads 82 for engagement with corresponding screw threads (not shown) on the shaft 14.
• the end of the passage 80 adjacent the belt-guiding section 50 is countersunk to provide a smooth chamfered edge 84 (Fig. 6) to facilitate installing the pulley 10 on the shaft 14 and for weight reduction.
• the belt-guiding section 50 extends from the second (left) end wall 62 of the hub 52. It has a conical external surface 86 which flares outward from the inner face 72 of the second end wall 62 to an end 88 of the body.
• the surface 86 and belt-guiding section 50 covers a portion of the drive shaft 14 to prevent the belt 16 from engaging that portion instead of the hub 52. Further, the belt guiding section 50 provides a self-alignment capability. If the belt 16 is at an incorrect position contacting the belt-guiding section 50, the belt will "walk” down the sloping external surface 86 to the correct position as the pulley 10 rotates. Because the pulley 10 is made in one-piece, the belt guide cannot be installed in a backwards orientation. [0028] In the embodiments shown in the drawings (Figs. 6 and 7), the
• the external surface 86 of the belt-guiding section 50 has a smooth and continuous (uninterrupted) contour and is connected to the inner face 72 of the second end wall 62 by a smooth convex transition 90 having a radius R which transitions between the relatively steep slope of the second end wall 62 and the lesser slope, of the external surface 86 of the belt-guiding section 50.
• the belt-guiding section 50 also has an internal surface 92 (Fig. 6) which extends from the internal passage 80 and outer face 74 of the second end wall 62 to the end 88 of the body.
• the internal surface 92 is substantially free of reinforcing members and defines a hollow, cup-shaped interior 94 free from structure within the interior. That avoids manufacturing complexities, weight, and failure-prone components associated with a collar or ribbed structure inside a belt guide. Further, the shaft 14 can extend through the interior 94 of the belt-guiding section 50 without contacting any structure therein.
• the pulley 10 is produced by a die casting process to avoid the need for machining and thereby providing lower cost.
• An exemplary process is multi-slide diecast process which is proprietary to Dynacast International Limited, having international headquarters in Warwickshire, England and North American offices in Danbury, Connecticut. Further discussion of such a process is found in U.S. Patent No.
• the process uses several (e.g., four) perpendicular slides to enable complex and accurate castings.
• the multi-slide process is effective for forming parts with complex geometries, especially an internally screw-threaded article, such as the pulley. It minimizes discontinuities in surface contours (referred to as "parting lines") which are frequently found on die cast parts and must be removed by machining.
• parting lines discontinuities in surface contours (referred to as "parting lines") which are frequently found on die cast parts and must be removed by machining.
• a discontinuity on or adjacent the ribs 54 of the belt-driving section 40 is of critical importance because it would abrade the belt 16 and lead to its failure.
• the pulley 10 is made of a material suitable for molding and which exhibits high strength, durability and hardness, low cost raw material, and is resistant to corrosion.
• the pulley 10 is made of zinc or a zinc alloy. It is understood that the pulley could be made of other materials without departing from the scope of this invention.
• An alternate embodiment 100 of the pulley which is press fit on a shaft is shown in Fig. 7.
• the internal passage 80 in the pulley 100 includes a plurality of straight-wall longitudinal splines 102 (e.g., six splines). It is understood that the number and/or configuration of splines may vary without departing from the scope of this invention.
• Splines 102 enable the pulley 10 to be press fit on an end of a drive shaft 14 having a corresponding splined geometry (not shown).
• the first end wall 60 may be used as a grip for holding the shaft 14 stationary and preventing its rotation while rotating the blower during installation to, or removal from, the opposite end of the shaft. Therefore, other than the external splines engaging the pulley, the shaft 14 does not need to have a flat surface, slot, or any deformation which is typically added, as known to those skilled in the art, to facilitate holding the shaft and which typically removes material from a cylindric shaft. Therefore, the shaft 14 of the present invention remains generally solid and cylindric which leaves it comparatively stronger.
• the shaft 14 is not limited to a type of steel which is machinable.
• Yet another embodiment (not shown) of the pulley has an internal passage 80 comprising a smooth bore which is press fit over an end of a drive shaft 14 having a splined geometry.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Pulleys (AREA)
• Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)

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• 2004
  • 2004-05-17 US US10/847,432 patent/US7204774B2/en active Active
• 2005
  • 2005-04-28 MX MXPA06013334A patent/MXPA06013334A/es active IP Right Grant
  • 2005-04-28 WO PCT/US2005/014744 patent/WO2005116490A1/en active Application Filing
  • 2005-05-17 CN CNU2005200190248U patent/CN2830790Y/zh not_active Expired - Lifetime

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